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Direct Numerical Simulation of the Flow over a Golf Ball

abstract: The flow around a golf ball is studied using direct numerical simulation (DNS). An immersed boundary approach is adopted in which the incompressible Navier-Stokes equations are solved using a fractional step method on a structured, staggered grid in cylindrical coordinates. The boundary conditions on the surface are imposed using momentum forcing in the vicinity of the boundary. The flow solver is parallelized using a domain decomposition strategy and message passing interface (MPI), and exhibits linear scaling on as many as 500 processors. A laminar flow case is presented to verify the formal accuracy of the method. The immersed boundary approach is validated by comparison with computations of the flow over a smooth sphere. Simulations are performed at Reynolds numbers of 2.5 × 104 and 1.1 × 105 based on the diameter of the ball and the freestream speed and using grids comprised of more than 1.14 × 109 points. Flow visualizations reveal the location of separation, as well as the delay of complete detachment. Predictions of the aerodynamic forces at both Reynolds numbers are in reasonable agreement with measurements. Energy spectra of the velocity quantify the dominant frequencies of the flow near separation and in the wake. Time-averaged statistics reveal characteristic physical patterns in the flow as well as local trends within dimples. A mechanism of drag reduction due to the dimples is confirmed, and metrics for dimple optimization are proposed. / Dissertation/Thesis / Ph.D. Mechanical Engineering 2011

Identiferoai:union.ndltd.org:asu.edu/item:14352
Date January 2011
ContributorsSmith, Clinton Elliott (Author), Squires, Kyle D (Advisor), Balaras, Elias (Committee member), Herrmann, Marcus (Committee member), Adrian, Ronald (Committee member), Stanzione, Daniel C (Committee member), Calhoun, Ronald (Committee member), Arizona State University (Publisher)
Source SetsArizona State University
LanguageEnglish
Detected LanguageEnglish
TypeDoctoral Dissertation
Format229 pages
Rightshttp://rightsstatements.org/vocab/InC/1.0/, All Rights Reserved

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